Week 5

Question 1

How is movement (skilled movement, posture, and spinal reflexes) organized?

Answer 1

Question 2

Define voluntary movement

Answer 2

Question 3

How is the nervous system organized?

Answer 3

Question 4

Describe the gross anatomy of the spinal cord

Answer 4

Question 5

Explain segmental organization of the spinal cord

Answer 5

Question 6

List the spinal nerve innervation of skeletal muscles

Answer 6

Question 7

Explain white and gray matter of the spinal cord

Answer 7

Question 8

What are the regional differences of gray matter?

Answer 8

Cervical
- Oval shape
- Greatest amount of white matter - lots of tracts!
- Dorsal intermediate sulcus is present only in cervical region to T6
* Intermediate sulcus separates 2 tracts getting information from different areas of the body
- Big ventral horns C5-8 for brachial plexus
- In cervical region, spinal cord aligns with vertebrae

Thoracic
- Presence of lateral horn
- Small amount of gray matter, no plexus because it does not innervate and control any limbs
- Dorsal intermediate sulcus (T6 & above)

Lumbar
- Largest ventral horn: lumbosacral plexus
- Least amount of white matter (less motor tracts, more PNS)
* Tracts ascend, so you collect tracts as you ascend from the lumbar to the cervical regions of the spinal cord (the lumbar region only has lumbar and sacral tracts, while the cervical region has sacral, lumbar, thoracic, and cervical tracts)
- No dorsal intermediate sulcus
- Spinal cord ends (L1-L2 Intervertebral space)
- Cauda equina (long roots of the spinal nerves) present (L2 and below)
- Filum terminale (connective tissue that connects end of the SC to the coccyx)

Question 9

Label

Answer 9

Question 10

Label

Answer 10

Question 11

What are the sensory tracts of white matter?

Answer 11

Question 12

What are the motor tracts of white matter?

Answer 12

Question 13

Describe primary, secondary, and third order neurons

Answer 13

Question 14

What are the first order neurons of the spinal cord? Where do they go?

Answer 14

Question 15

What are the second and third order neurons of the spinal cord? Where do they go?

Answer 15

Question 16

Explain what the somatosensory areas are

Answer 16

Question 17

How is the cerebrum organized?

Answer 17

Question 18

Explain the signal route of discriminative touch and conscious proprioception

Answer 18

Question 19

Label

Answer 19

Question 20

What are the spinothalamic tracts?

Answer 20

Question 21

Explain fast vs slow pain in the spinothalamic tracts

Answer 21

Question 22

Which is fast?

Answer 22

A) fast
B) slow

Question 23

Explain the primary, secondary, and third order neurons of the anterolateral system

Answer 23

Question 24

What is the route of signal transmission in the anterolateral system?

Answer 24

Question 25

What is the organization of the anterolateral system?

Answer 25

Question 26

What is the route of signal transmission in slow nociceptive tracts?

Answer 26

Question 27

Label

Answer 27

Question 28

Where are the spinocerebellar tracts?

Answer 28

Question 29

What are the spinocerebellar pathways?

Answer 29

Question 30

Describe unconscious proprioception

Answer 30

Question 31

Explain signal route of transmission for unconscious proprioception of posterior spinocerebellar tract from L/E and lower body

Answer 31

Question 32

Explain signal route of transmission for unconscious proprioception of cuneocerebellar tract from U/E and upper body

Answer 32

Question 33

Explain signal route of transmission for unconscious proprioception of anterior spinocerebellar tract from L/E and lower body

Answer 33

Question 34

Label

Answer 34

Question 35

Explain the descending pathways

Answer 35

Question 36

Explain lateral and medial corticospinal tracts

Answer 36

Question 37

What is the route of signal transmission in the corticospinal tract?

Answer 37

Question 38

Label

Answer 38

Medial (anterior) CST

Question 39

Label

Answer 39

Question 40

What are the anatomical components of the corticospinal tract?

Answer 40

* Corona Radiata * Internal Capsule * Cerebral peduncle * Pyramid * Corticospinal fibers

Question 41

Label

Answer 41

Question 42

Explain the anatomy of CST

Answer 42

Question 43

What is the CST organization of LMNs in the spinal cord?

Answer 43

Question 44

Answer 44

1. Cerebral Cortex Lesion (Uppermost X) A lesion in the primary motor cortex disrupts signals before they travel down the corticospinal tract, causing contralateral motor deficits. This could lead to contralateral hemiparesis or hemiplegia, affecting voluntary movement and coordination on the opposite side of the body. 2. Midbrain Lesion (Middle X) Damage at the midbrain level affects descending motor fibers before they cross in the medulla, resulting in contralateral weakness or paralysis. If surrounding structures are involved, this could lead to syndromes like Weber’s syndrome (which includes ipsilateral oculomotor palsy with contralateral hemiparesis). 3. Spinal Cord Lesion (Lowest X - After Decussation) Since the corticospinal tract has already decussated at the medulla, damage in the spinal cord leads to ipsilateral motor deficits. This means muscle weakness, spasticity, or paralysis occurs on the same side as the lesion, affecting movement and reflex control below the injury level.

Question 45

What is the function of spinal cord interneurons?

Answer 45

Modulate descending drives and integrate sensory inputs with motor output

Question 46

Explain the stepping generator pattern of interneurons

Answer 46

Question 47

Explain

Answer 47

Question 48

Provide an example of withdraw reflex

Answer 48